Objective To determine the distribution of GAD67 and GAD65 mRNAs in the rhesus monkey. ABSTRACT:Samples of total RNA isolated from the preoptic area, medio-basal hypothalamus, posterior hypothalamus, hippocampus, liver and placenta were subjected to RT-PCR analysis for GAD67 and GAD65 mRNAs. A single band of 211 base pairs (bp) for GAD67 was present in all brain samples, but not in the liver or placenta. Similarly, specific amplification from the same reverse transcription reactions revealed the expected cDNA of 382 bp, and an additional band of approximately 232 bp for GAD65, although the relative amounts of GAD65 amplification product were consistently lower than those of GAD67 in all brain samples. All bands were subcloned and sequenced, and the 211 and 382 bp bands represented previously cloned GAD 67 and GAD65 cDNAs, respectively. However, the 232 bp fragment for GAD65 had a novel deletion of 150 bp, which would result in a predicted protein lacking amino acids 46-95. To our knowledge, the gene coding for the GAD65 mRNA has not been sequenced in any species. The functional significance of these results remains to be determined. Keywords GAD67 mRNA, GAD65 mRNA, cDNA sequences for GAD67 and GAD65, alternative splicing